Annular linear flow electromagnetic induction pumps for impelling liquid metals generally comprise an annular flow channel or duct which is surrounded by a column composed of a multiplicity of alternating annular stator coils and magnetic stator iron. This type of electromagnetic pump, commonly known as a single stator, annular linear flow induction pump, and its use in a liquid metal cooled nuclear fission reactor, is disclosed in U.S. Pat. No. 4,859,885, issued Aug. 22, 1989, and U.S. Pat. No. 4,882,514, issued Nov. 21, 1989.
However a more versatile linear flow electromagnetic induction pump design than those shown in the above patents comprises a double stator system. This electromagnetic pump system comprises the single stator arrangement as shown in the aforesaid patent, which is additionally provided with a second or inner stator arrangement concentrically contained and enclosed within the aforementioned pump central linear liquid flow duct or channel. A second stator column is also composed of a multiplicity of alternating annular stator coils and stator iron. In combination, the outer and inner, or double stators act upon the liquid linearly passing through the annular flow duct.
This double stator arranged pump design provides greater pumping capacity per pump unit size, or alternatively equal capacity provided by a smaller pump unit. Accordingly the double stator pump has the advantages of greater efficiency and versatility, among others.
The disclosures and contents of the aforesaid U.S. Pat. Nos. 4,508,677, 4,859,885 and 4,882,514, are incorporated herein by reference.